The portable printer includes a printer that is configured to print on a printing paper. As the portable printer, a label printer is known, e.g., that includes a function for ejecting a label by separating the label from a strip-shaped mount (e.g., Patent Literature 1).
The portable printer is configured to print a value or a barcode on the label at a store or a place of sales. The label is attached to merchandise. In such a case, the portable printer is operated while being held by the hands of an operator, or operated while being attached to a body of the operator via clothing or a belt (e.g., Patent Literature 2).